﻿/***************************************************COPYRIGHT***************************************
* Copyright (c) 2008, Whiteboard-IT
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification, are permitted provided that 
* the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this list of conditions and the following 
 * disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following
 * disclaimer in the documentation and/or other materials provided with the distribution.
*
* Neither the name of Whiteboard-IT, LLC nor the names of its contributors may be used to endorse or promote 
 * products derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, 
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON 
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
*****************************************************************************************************************/
using System.Collections.Generic;
using System.Linq;

namespace Mite
{
	/// <summary>
	/// Represents a Foreign Key relationship between <see cref="Column"/>s in seperate tables.
	/// </summary>
	public class ForeignKey : TableConstraint
	{
		private Dictionary<Column, Column> referenceMap = new Dictionary<Column, Column>();

		/// <summary>
		/// Creates an instance of foreign key that assumes the foreign key is a constraint on 
		/// <paramref name="table"/> to the primary key of <paramref name="referenceTable"/>.
		/// Adds columns to <paramref name="table" /> for each column that is a member of
		/// <paramref name="referenceTable"/>'s primary key.
		/// </summary>
		public ForeignKey(Table table, Table referenceTable)
		{
			Table = table;
			ReferenceTable = referenceTable;

			foreach (var refColumn in referenceTable.Columns.Where(col => col.IsPrimaryKey))
			{
				Column column = refColumn.CloneColumn();
				column.Name = refColumn.Table.Name + refColumn.Name;

				table.AddColumn(column);

				referenceMap.Add(column, refColumn);
			}
		}

		/// <summary>
		/// Table that this foreign key constraint references.
		/// </summary>
		public Table ReferenceTable { get; private set; }

		/// <summary>
		/// Map of member columns of <see cref="ForeignKey.Table"/> to
		/// member columns of <see cref="ReferenceTable"/>.
		/// </summary>
		public IEnumerable<KeyValuePair<Column, Column>> ReferenceMap { get { return referenceMap; } }

		/// <summary>
		/// Columns in <see cref="ForeignKey.Table"/> that are members of this
		/// foreign key.
		/// </summary>
		public IEnumerable<Column> Columns
		{
			get { return referenceMap.Keys; }
		}

		/// <summary>
		/// Update rule for relationship.
		/// </summary>
		public ForeignKeyRule UpdateRule { get; set; }

		/// <summary>
		/// Delete rule for relationship.
		/// </summary>
		public ForeignKeyRule DeleteRule { get; set; }
	}
}